I recently got my hands on a TP-LINK TL-WR841ND v7.2 wireless router. I wanted to flash its art partition to remove all Tx power caps and only have the regulatory domain limits apply, as I have already done with several others of the same brand. However, this particular model and revision uses a AR9287 chip, unlike my other routers, which were all AR93xx. Its ART layout is completely different, and thus pepe2k's excellent ar9300_eeprom tool reads (and writes) bogus values.
I found structs for the AR9287's EEPROM here, and they appear to match the contents of my partition. I tried editing the regdomain, but after flashing the new data, I discovered it has an integrity check (although the expected checksum shows up in dmesg, so in theory it should be possible to fix it and reflash). At this point, I halted all further testing, restored the original ART and decided to start this thread.
What is known about the AR9287's art partition layout? Are "high power" modifications possible? This post says the TL-WR841ND v7.x can transmit at up to 27 dBm merely by using a special OpenWrt build. But even after applying reghack2 (which should be the equivalent of "Force Atheros drivers..." for the 00 and US regions, my EEPROM being locked to the latter), I can't get mine to go above 21 dBm. All the other information I was able to find applies to PCI wireless cards using this chip, not routers, but I'll leave it here for reference.
Ath EEPROM Tool
How to change Atheros AR9xxx aka ath9k EEPROM values
Support 802.11n on cards with Atheros AR9xxx chips
Rebranding the Atheros 928x cards - The guide
Atheros 9K Series ROM Modding Tools And Recovery Kit
Also, here's a dump of my router's ART in case anyone wants to investigate (run echo UEsDB... | base64 -d - > art.zip in a terminal to get the file, then unzip).